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Enhancement in thermoelectric power factor of polycrystalline Bi 0.5 Sb 1.5 Te 3 by crystallite alignment
Author(s) -
Dehkordi Arash Mehdizadeh,
Vashaee Daryoosh
Publication year - 2012
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201228147
Subject(s) - crystallite , seebeck coefficient , thermoelectric effect , materials science , scanning electron microscope , thermoelectric materials , electrical resistivity and conductivity , diffraction , analytical chemistry (journal) , composite material , thermal conductivity , optics , metallurgy , chemistry , electrical engineering , physics , thermodynamics , chromatography , engineering
It is known that the random orientation of crystallites in polycrystalline Bi 0.5 Sb 1.5 Te 3 reduces its thermoelectric power factor. An efficient method for growing ordered bulk polycrystalline Bi 0.5 Sb 1.5 Te 3 was used and the enhancement of thermoelectric power factor was demonstrated. For comparison, samples with randomly and preferentially oriented crystallites were sintered from similar powder of Bi 0.5 Sb 1.5 Te 3 . A press process similar to extrusion was used to align the crystallites during the hot press. The crystallites alignment was verified by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The dominant orientation in the aligned sample was in c ‐plane (0,0,15). The aligned sample demonstrated significant increase in electrical conductivity while the Seebeck coefficient remained unchanged. As a result, the thermoelectric power factor of the aligned sample was improved by ∼50%.